Wobble plate pump

ABSTRACT

A wobble plate pump for transporting sewage, viscous liquids and industrial effluents. An impeller disc is obliquely mounted to a drive shaft and a pair of shrouds are attached to the impeller disc to provide static and dynamic balance. A pair of vanes are provided to increase efficiency and are mounted on opposite sides of the impeller disc.

O United States Patent 1 91 1111 3,865,503

Gearhart Feb! 11, 1975 [54] WOBBLE PLATE PUMP :eig: 4l5/70 6 4l5/70 [751 Inventor: y State co'lege1 3,375,983 4/1968 vz n Eiff et al. 415/70 [73] Assignee: The United States of America as Primary Examiner-C. .l. Husar represented by the Secretary of the Assistant Examiner-Leonard Smith Navy, Washington, DC. Attorney, Agent, or Firm-R. S. Sciascia; Paul S. 221 Filed: 0a. 15, 1973 [2]] Appl. No.: 406,767 [57] ABSTRACT A wobble plate pump for transporting sewage, viscous U-So n a s H CL mounted to a drive Shaft and a of [58] new of Search 15/7 shrouds are attached to the impeller disc to provide 415/88 143 static and dynamic balance. A pair of vanes are provided to increase efficiency and are mounted on oppo- [56] References C'ted S site sides of the impeller disc.

UNITED STATES PATENT 2,956,503 10/1960 Neidl 415/70 4 6 Drawmg PMENTED FEB SHEET 1 [IF 2 Fig.1

PATENKDFEBJ 1 I975 SHEET 2 OF 2 T T 3, ggNDT D WHAFT MOMENT AFTER 180 OF ROTATION jaws 32 *lpl (PRIOR ART) F |g.3 (b) 75 SHROUDS CENTROID OF SHROUDED DISC N N 4 O) HAVING DIS WOBBLE PLATE PUMP BACKGROUND OF THE INVENTION The present invention relates to a pump for transporting sewage. viscous liquids and industrial effluents and particularly to a wobble plate pump which has exceptional resistance to clogging when pumping fluids containing solids and stringy materials.

Centrifugal pumps having special constructions have been used for delivering sewage, thick slurries and the like. These pumps, however, are easily clogged because the solids get stuck in the channels of the centrifugal pump and also jam in the point of transition between the rotating and stationary portions of the pump.

In order to overcome the clogging effect of centrifugal pumps, wobble pumps have been employed where the impeller is constructed as a disc. This disc is secured obliquely on the pump shaft so that when the impeller is rotating, the edges of the impeller discs working surface facing towards the suction intake describe a circle. The main disadvantage of heretofore known wobble pumps is that the impeller disc was not balanced and the pumps were subjected to vibration and subsequent bearing failure.

SUMMARY OF THE INVENTION The present invention relates to a wobble plate pump having a flat impeller disc obliquely mounted to a shaft and the disc and shaft are statically and dynamically balanced. A pair of spherically shaped shrouds are attached to the periphery of the impeller disc and extend one each on each side of the disc. A pair of runner vanes are also provided and are mounted one each on each side of the disc.

It is therefore a general object of the present invention to provide an improved pump for transporting sewage, viscous liquids and industrial effluents.

Other objects, advantages, and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view showing a wobble plate having shrouds attached thereto;

FIG. 2 is a sectional view of a preferred embodiment of the present invention;

FIG. 3(a) and 3(b) are diagrammatic views showing a prior art wobble plate;

FIG. 4 is a diagrammatic view showing a wobble plate of the present invention; and

FIG. 5 is a diagram comparing performance of a prior art wobble pump and the pump of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, a flat impeller disc 11 having front and rear parallel surfaces is mounted at an inclined angle to shaft 12 by means of screws 13. Disc 1] has a plurality of bosses 14 to provide sufficient thickness for tapped holes, and a pair of spherically shaped shrouds l5 and 16 are attached to disc 11 by screws 17. Impeller disc 11 is rotatable in housing 18, which is shown to have two inlets 21 and 22, with the fluid being discharged from two separate cavities 23 and 24 into a single volute having an opening 25. Shaft 12 is rotatably mounted in bearings 26 and shaft 12 is' adaptable to be driven by a motor (not shown). A pair of runner vanes 27 and 28 are attached to opposite sides of impeller disc 11 and significantly improve the performance of the wobble plate pump. As best shown in FIG. I of the drawings, vane 28, which is identical to vane 27, has its smallest cross-sectional area near the center of disc 11 and vane 28 tapers outwardly so that its greatest cross-sectional area is at the outer edge of disc 11. Vanes 27 and 28 are diametrically opposed one another. but on different surfaces of disc 11.

Referring now to FIGS. 3(a) and 3(1)) of the drawings, there is shown a prior art arrangement of a disc 31 mounted obliquely to a shaft 32. As shown. the centroids of disc 31 are displaced a distance I and. as shaft 12 is rotated, the shaft moment is completely re versed after of rotation. FIG. 4 of the drawings depict the present invention wherein proper weighting of shrouds l5 and 16 reduces the time varying shaft moment to zero. FIG. 5 of the drawings compares the output, in gallons per minute, of the prior art arrangement shown in FIG. 3 with a device constructed according to the teachings of the present invention having a disc 6 inches in diameter. The experimentally measured head and flowrate indicates that the wobble plate pump of the present invention has a specific speed within the range of a centrifugal pump, that is, has a similar capacity and head at a given shaft speed. The efficiency of a pump constructed having a 6 inch diameter was about 36 percent, which is equivalent to the efficiency for small centrifugal pumps of similar capacity. The pump having a disc ll 6 inches in diameter was tested at speeds of 1,150 RPM and 1,750 RPM and the operation of the pump was very quiet and free of vibration.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

I claim:

1. A wobble plate pump for transporting viscous liquids comprising,

a stationary housing having at least one inlet and at least one outlet,

a rotatable shaft extending axially into said stationary housing,

an impeller disc having front'and rear parallel surfaces. said impeller disc being attached to said shaft with said surfaces being in planes inclined to the axis of said shaft, and

first and second spherically shaped shrouds attached to said impeller disc for providing static and dynamic balance to said shaft and impeller disc.

2. A wobble plate pump for transporting viscous liquids as set forth in claim 1 wherein said first and second spherically shaped shrouds are diametrically opposed with said first shroud extending to partially cover said front surface of said impeller disc and said second shroud extending to partially cover said rear surface of said impeller disc.

3. A wobble plate pump for transporting viscous liquids as set forth in claim 1 having a first runner vane attached to said front surface of said impeller disc and a second runner vane attached to said rear surface of said impeller disc.

4. A wobble plate pump for transporting viscous liquids as set forth in claim 3 wherein said first runner vane is diametrically opposed to said first spherically shaped shroud and said second runner vane is diametrically opposed to said second spherically shaped shroud. l k l I 

1. A wobble plate pump for transporting viscous liquids comprising, a stationary housing having at least one inlet and at least one outlet, a rotatable shaft extending axially into said stationary housing, an impeller disc having front and rear parallel surfaces, said impeller disc being attached to said shaft with said surfaces being in planes inclined to the axis of said shaft, and first and second spherically shaped shrouds attached to said impeller disc for providing static and dynamic balance to said shaft and impeller disc.
 2. A wobble plate pump for transporting viscous liquids as set forth in claim 1 wherein said first and second spherically shaped shrouds are diametrically opposed with said first shroud extending to partially cover said front surface of said impeller disc and said second shroud extending to partially cover said rear surface of said impeller disc.
 3. A wobble plate pump for transporting viscous liquids as set forth in claim 1 having a first runner vane attached to said front surface of said impeller disc and a second runner vane attached to said rear surface of said impeller disc.
 4. A wobble plate pump for transporting viscous liquids as set forth in claim 3 wherein said first runner vane is diametrically opposed to said first spherically shaped shroud and said second runner vane is diametrically opposed to said second spherically shaped shroud. 